Hypersensitive and color-tunable temperature sensing properties of (Eu,Tb)(AcAc)3phen via phonon-assisted energy transfer

Abstract

In this paper, the temperature sensing properties of (Eu,Tb)(AcAc) 3 phen (AcAc − and phen stand for acetylacetonate and 1,10-phenanthroline, respectively) are reported. This temperature sensor uses fluorescence intensity ratio (FIR) between emissions of Eu 3+ (red) and Tb 3+ (green). While the molar ratio between Eu 3+ and Tb 3+ is 1, the relative sensitivity keeps high value (>3%∙K −1 ) near room temperature (−40 °C–50 °C), reaching its maximum as 4.1%∙K −1 . In addition, the minimum of temperature uncertainty (0.0043 K) is superior to those reported in literature in our knowledge. The emission color of sample is acutely temperature sensitive (green to red). The temperature sensing mechanism is via phonon-assisted energy transfer. It is proved that the major energy transfer route is from 5 D 4 (Tb 3+ ) to 5 D 1 (Eu 3+ ). Moreover, the functional relationship between FIR and absolute temperature T is demonstrated by rate equations firstly in phonon-assisted energy transfer case. • Relative sensitivity keeps high value (>3%∙K −1 ) near room temperature. • Minimum of temperature uncertainty (0.0043 K) is superior to other reported values. • Emission color of sample is acutely temperature sensitive (green to red). • Functional form between FIR and T is demonstrated firstly in energy transfer case.